1. Field of the Invention
The present invention relates to a device for applying imbalance to a rotor.
2. Description of the Prior Art
It is known that to balance rotors by the coefficients of influence method it is necessary to add imbalance to the rotor in order to carry out measurements with and without the imbalance.
To add imbalance it is necessary to stop the rotor, as a result of which the measurements carreid out with and without imbalance are separated by a number of hours or even days and, by virtue on the one hand of the time lapse and on the other hand of the fact that the rotor has been stopped, the coefficient of influence deduced from the measurements may be different from the true coefficient of influence (see FIG. 1).
There exists a device known from document DE-A No. 3102726 permitting imbalance to be applied to a rotor without stopping the latter, said device comprising, on the one hand, a plurality of chambers disposed symmetrically around the rotor, said chambers being adapted to contain a fluid and provided with an opening, and, on the other hand, a plurality of opening devices associated with the chambers, each device being remotely controllable via a wire to open the opening in the associated chamber, so that the fluid contained may be evacuated.
In the known device, the opening devices are controlled via wires wound on the rotor, which raises major problems of implementation due to centrifugal force and the environment (water vapor, water, etc.) resulting in unreliable results with regard to transmission of commands. Also, it is extremely difficult when the rotor is not drilled to connect these wires to the exterior through the intermediary of a rotary contact assembly.